I have used Campaign Monitor for the past 3+ years.  Before Campaign Monitor I used various other providers (ExactTarget, SilverPop, MailChimp) as well as some homegrown solutions.

Please don’t ever use Outlook or regular email to send out a newsletter to more than 10 people.  The risks are not worth the tiny amounts of money you “save”.

Why I use Campaign Monitor

1. Easy to add signup forms to your site.
2. It’s cheap -  $5 per send and 1¢ per recipient
3. They have really nice reports - the reporting is similar to Google Analytics
4. They have built in auto-scrubbing of lists.  Old emails are automatically cleaned out of your lists.
5. Emails are easy to customize - I can either use my own html/images or pick one of their existing templates
6. There is free preview & testing of emails.  Emails are hard to get right across all the different clients (don’t even get me started on lotus notes )
7. There service is reliable.  I haven’t had any issues in the 3+ years I have used their service.
8. They are experts in their industry.  Their blog is top-notch.  They often post research & tips that really and truly help.  For example, check out this post about CSS support in email clients.
9. They have a powerful API. 
10. They have serious reputable clients (this can help if you ever need to justify a decision to someone).

Below is my list of everything I try and do to promote a new website.  I will at least seriously consider ever one of these below items, you should too:

• setup thoughtful content including meta keyword, meta description, title & alt tags for images
• identify similar sites & send out link reciprocity requests
• join a network like 9 rules (research industry specific sites)
• setup a blog
• setup a RSS feed
• setup an email newsletter
• add tell a friend links on key pages (product pages)
• submit site to search engines and directories see my list of sites I submit to
• submit site to design galleries & industry sites
• join industry forums & post with an email signature (keep on topic & not spammy)
• setup your email with a signature with your site URL & tagline
• make up bumper sticker’s for your cars with the site URL
• give out samples to prominent sites/blogs in exchange for reviews or at least links
• setup contests/giveaways on your site or other’s sites (maybe tie it to newsletter signups for entry)
• go old school and have business cards printed (authors should print bookmarks instead) 
• tell people you meet in person about the site and handout business cards
• network at industry events & handout business cards 
• add your URL to your social networking profiles (linkedin, facebook, myspace, facespace )
• create a widget that people can put on their sites to promote yours
• setup a google XML sitemap
• use paid advertising like google adwords & text links